The present invention relates to a method of modifying the surface of a particle comprising a magnetic particle. For example, it relates to the method of modifying the surface of a bead for use in bead agglutination to detect an antigen-antibody reaction.
Bead agglutination is one of the techniques to detect an antigen-antibody reaction used in immunoassays. In bead agglutination, fine particles such as plastic beads having antibodies adhered to their surfaces are used in carrying out reaction with associated antigens and the degree of agglutination of beads is measured to detect and identify very small amounts of antigen and antibody. In the conventional method of bead agglutination, a polystyrene bead is used as a plastic bead but its affinity for antibody is too low to have them adhere to each other in sufficient amount to ensure precise detection and identification.